A fast bowler from Wellington, Iain O'Brien earned his first Test call-up in March 2005 when New Zealand's pace stocks were hit by injury problems. He had had a solid State Championship that season, taking 20 wickets at 26.55, but his impact in his two Tests against Australia was limited. O'Brien managed only one wicket in each match and faded from the national selectors' radar until 2006-07, when he was included in Test and ODI squads for Sri Lanka's tour of New Zealand. He wasn't used, however, and had to settle for being the leading wicket-taker in the State Championship with 34 victims at 20.85. Those figures were enough to keep him in the frame and he finally added to his Test tally in South Africa in November 2007 after he was a late replacement in the touring party because of an injury to Kyle Mills.

O'Brien shunts between New Zealand and England to be with his English wife, who lives in Derbyshire. Writing is one of his hobbies and apart from managing his own blog, he contributes to a local Derbyshire cricket website. In December 2009, he retired from international cricket to spend more time with his family in England, and joined Middlesex as a replacement for Murali Karthik. Cricinfo staff April 2010